As a method for hydrogen production based on chemical decomposition of water, there are known those such as, for example, the reaction of a metal with an acid or water, thermal decomposition and electrolysis. The reaction of metal with an acid or water can be carried out at room temperature, but it is difficult to use it industrially because of its low productivity. For this reason, the thermal decomposition and electrolysis of water have been used on an industrial scale. However, these methods require a large quantity of electric energy or thermal energy, resulting in increase in manufacturing cost.
The present invention is made from such a background. It is well known that aluminum reacts with oxygen in air at room temperature and passivation occurs owing to the formation of a highly stable oxide film on its surface. This oxide film provides resistance to corrosion by seawater and other aqueous and chemical solutions, so that aluminum and its alloys are employed in various applications. The inventors of this invention have now found that a binary aluminum alloy containing a certain amount of tin reacts with water even at room temperature and produces hydrogen without use of any chemicals. It has also been found that the rate of hydrogen production varies significantly with increasing tin content and with increasing temperature of water.